Final answer:
Ellis was able to quickly find and fix the problem. Therefore, the correct option is 1.
Step-by-step explanation:
Ellis found the issue and resolved it swiftly. Although "mend" and "repair" are somewhat interchangeable with "fix," the term "fix" is more frequently used to refer to the process of locating and effectively fixing an issue. The term "fix" refers to a straightforward and satisfactory settlement; it is frequently used informally.
In this instance, "fix" denotes that Ellis found the problem quickly and fixed it without requiring significant patching or repairs. "Fix" would therefore be the best word to finish the phrase.
Therefore, the correct option is 1.